Household steam treatment device and method for operating a household steam treatment device

Description

[0001] The invention relates to a household steam treatment appliance, comprising a steam treatment chamber that can be closed by a door, a steam generating device for generating steam, a water tank for providing liquid for the steam generating device, and a pump for pumping liquid from the water tank to the steam generating device. The invention is particularly advantageously applicable to household appliances for steaming food, especially to steam cooking appliances.

[0002] DE 10 2012 109 631 A1 discloses a cooking appliance with a cooking chamber for treating food and with a steam generating device for generating steam. The water used to generate the steam can be supplied to the steam generating device via a coupling device. The coupling device has a connection device suitable for connection to a fixed water supply. A conduit device is provided between the connection device and the steam generating device, which provides a flow connection suitable for conducting water and includes a free fall section. A water guide device is arranged in the free fall section.

[0003] FR 2958719 A1 discloses an oven having a cooking chamber formed in a housing and a steam generator that generates steam that can be introduced into the cooking chamber. A water fill valve supplies a hydraulic system with water from the steam generator. A water fill part comprises a water supply opening of the hydraulic system. A drain part has a water drain opening of the hydraulic system. The water supply opening and the water drain opening are accessible in an outlet position of the valve on an exterior side of the oven. Further prior art can be found in EP 3 076 086 A1.

[0004] It is the Task The aim of the present invention is to at least partially overcome the disadvantages of the prior art and, in particular, to provide a possibility for particularly simple and user-friendly use of a steam treatment device.

[0005] This object is achieved according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0006] According to the invention, the household steam treatment device, hereinafter referred to as steam treatment device, a steam generating device for generating steam, a water tank for providing liquid for the steam generating device and three pumps.

[0007] The use of the three pumps allows, in addition to the usual refilling of the steam generator with water from the water tank, a simple and user-friendly way to pump liquid into the device, drain liquid from the device, and / or circulate liquid within the device. Due to the pumping action of the pumps, the water tank and steam generator can also be positioned anywhere within the device, for example, above the steam treatment chamber.

[0008] In one embodiment, the steam treatment device has a steam treatment chamber that can be closed by a door. In another embodiment, the steam treatment device has at least one heating element for heating the steam treatment chamber and / or the goods contained therein and can then also be referred to as a steam cooking device, and its steam treatment chamber as a cooking chamber. The steam treatment device can be, for example, an oven with a steam treatment function, a microwave oven with a steam treatment function, or an oven with both a microwave and steam treatment function. Goods contained in the cooking chamber can be cooked without the addition of steam, cooked with the addition of steam, or treated with steam alone.

[0009] In a further development, the steam generation device can be a heatable water bowl embedded in the floor of the steam treatment chamber. In a further development, the steam generation device is arranged outside the steam treatment chamber, e.g., in the form of a boiler or a continuous-flow heater. The steam generator can be filled with liquid from the water tank using one of the pumps.

[0010] The steam generator has at least one heating element for steam generation. When activated, the heating element heats the water in the steam generator to boiling temperature. The resulting steam is introduced into the steam treatment chamber.

[0011] A further development is that the water tank is removable and can then typically be filled with water by the user. A further development is that the water tank is permanently installed in the device. It can then be filled with water by the user, for example, via a filling opening. Alternatively or additionally, the water tank can be filled with water via a fixed water connection.

[0012] The steam generator may have a fill level sensor. This may be configured, for example, to detect an empty state and / or when the steam generator has reached a maximum fill level. Depending on the current fill level, the steam treatment device can, for example, activate or deactivate at least one heating element, activate one of the pumps to add water, etc.

[0013] According to the invention, of the three pumps a pump ("first pump") is provided or arranged for pumping liquid from the water tank to the steam generating device, a further pump ("second pump") is provided for pumping liquid from the steam generating device to a receiving container and a further pump ("third pump") is provided for pumping liquid from the receiving container into the water tank.

[0014] This function of the three pumps advantageously enables, in addition to the usual refilling of the steam generation device with water from the water tank using the first pump, the pumping of any type of liquid into the device using the third pump in a particularly simple design, draining it from the device using the second pump, and / or circulating it within the device by activating or operating all three pumps. A further development is that the pumps can be activated or operated independently of one another, in particular by means of a control device of the steam treatment device.

[0015] The receptacle can be permanently installed in the device, be removably arranged within the device, or be fluidically connected to the device as a standalone receptacle, e.g., via a fluidic connection interface or "port" such as a connecting piece or a hose. The port is, in particular, an outwardly open passage opening that can be manually fluidically closed by a user, particularly by means of a closure element such as a plug or cap or similar.It is a further development that a suction-side connection or inlet of the first pump is connected to the water tank, a suction-side connection or outlet of the first pump is connected to the steam generating device, the steam generating device is further connected to an inlet of the second pump, an outlet of the second pump is connected to a connecting line leading to the receiving container, an inlet of the third pump is connected to a connecting line leading to the receiving container and an outlet of the third pump is connected to a connecting line leading to the water tank.

[0016] The pumps are liquid pumps. According to the invention, the pumps are self-locking pumps, i.e. they have a locking effect when inactive or switched off. This has the advantage that the number of components required can be kept to a minimum. However, instead of a self-locking pump, a functionally analogous arrangement of a non-locking pump (which allows liquid to pass through when switched off) and a check valve can also be used, e.g. in a fluidic series connection. The pump can be a positive displacement pump (volumetric pump) or a centrifugal pump, for example. A centrifugal pump has the advantage of being particularly quiet and robust. A positive displacement pump has the advantage that it can be designed to be self-locking particularly easily.

[0017] It is an embodiment according to the invention that an inlet of the first pump and an outlet of the third pump are connected to a common first connector which is fluidically connected to the water tank, an outlet of the first pump and an inlet of the second pump are connected to a common second connector which is fluidically connected to the steam generating device, and an outlet of the second pump and an inlet of the third pump are connected to a common third connector which is fluidically connected to a port for the receiving container.

[0018] This offers the advantage of a particularly simple and cost-effective design, which is also robust and particularly easy to install. The connecting pieces can, in particular, be shaped as pipes open at one end and, in particular, have two connecting pieces extending laterally for connection to the corresponding pumps. The connection to the water tank, the steam generator, or the port is then established, for example, via the open end. In a particularly compact design, the connecting pieces can be connected directly to the corresponding pump connections.

[0019] Alternatively, the output of the second pump may be fluidically connected to a first port and the input of the third pump may be fluidically connected to a second port.

[0020] According to the invention, the flow of fluid through a respective pump is blocked when the pump is not activated or not operating. For this purpose, the pump is designed as a self-locking pump or connected to a corresponding valve.

[0021] One embodiment provides for the connectors to be straight connectors arranged in an X-shape relative to one another. This results in a particularly compact arrangement. This is particularly advantageous when the connectors are arranged above the treatment chamber, as they can then be installed very flat. An X-shape can be understood in particular as meaning that two of the connectors are arranged at an angle or in an X-shape relative to one another, and the remaining connector is arranged parallel to one of the connectors arranged in an X-shape relative to one another.

[0022] In one embodiment, the connecting pieces are mechanically connected to one another. This advantageously achieves particularly simple handling, installation, and reliable mounting in the device. The mechanical connection can be form-fitting, force-fitting, and / or material-fitting. Thus, the two connecting pieces arranged parallel to one another can be manufactured as a single piece or welded, glued, and / or clamped together, etc. Connecting pieces arranged in an X-shape can, for example, be inserted into one another in a form-fitting manner, or welded, glued, and / or clamped together, etc.

[0023] One design allows the pumps to be arranged parallel to one another. This supports a compact design. For example, the pumps can be arranged horizontally next to one another above the treatment chamber. This also provides the advantage that the pumps can be easily connected to connectors arranged in an X-shape, particularly directly (i.e., without fluid-carrying intermediate pieces such as hoses, pipes, etc.).

[0024] One embodiment includes arranging the pumps in a shared water collection tray. This water collection tray offers the advantage that at least leaks from the pumps can be collected at the pump connections, preventing leakage fluid from flowing uncontrollably into the device and causing corrosion, for example. A further development includes arranging the connectors in this water collection tray. This advantageously also allows leaks at the connector connections to be collected.

[0025] One embodiment provides a drain for the water collection tray. This prevents uncontrolled overflow of the water collection tray, at least once a level predetermined by the position of the drain is reached.

[0026] A further development is that the drain leads into the water tank. This advantageously allows the leaked liquid to be recycled. It also eliminates the need for a separate drainage channel. A further development is that the drain is connected to a drainage channel leading to the outside (outside the device). This has the advantage that the leaked liquid does not remain inside the device. The drainage channel can lead to the outside, for example, in a base area of ​​the device.

[0027] One design is for the water collection tray to be manufactured as a single piece with the water tank, e.g., as a plastic injection-molded part. This simplifies production and assembly.

[0028] It is an embodiment that the steam treatment device can be operated in at least two operating modes, of which in a steam treatment mode, the second pump and the third pump are deactivated; and in a cleaning mode, all three pumps can be activated.

[0029] This provides the advantage of providing a conventional steam treatment mode for treating food in the cooking chamber and a particularly effective cleaning mode in a resource-saving manner. The steam treatment device can have multiple steam treatment modes. The steam treatment device can also have additional modes, e.g., a keep-warm mode, a pyrolysis mode, etc.

[0030] Specifically, in cleaning mode, activating or operating all three pumps can create a cleaning fluid circuit (e.g., as part of a cleaning program), enabling particularly thorough cleaning. The cleaning fluid can have a disinfectant, antimicrobial, and / or descaling effect. In a further development, the cleaning fluid can be a descaling fluid, possibly with additional antimicrobial action.

[0031] The object is also achieved by a method for operating a steam treatment device, in which in the cleaning mode a) the third pump is activated to pump cleaning liquid from the receiving container into the water tank; b) the first pump is activated to pump the cleaning liquid from the water tank into the steam generating device and c) the second pump is activated to pump the cleaning liquid from the steam generating device into the receiving container.

[0032] The process can be designed analogously to the steam treatment device and has the same advantages.

[0033] One embodiment involves performing steps a) to c) sequentially, meaning that step b) is only performed after step a) is completed, and step c) is only performed after step b) is completed. This provides the advantage of allowing the cleaning fluid to remain in contact for a sufficiently long time in a particularly simple manner. In particular, this also allows the amount of cleaning fluid required to be kept to a minimum.

[0034] One embodiment provides for contact breaks between steps a) to c). These can be the same or different. This has the advantage of achieving particularly effective cleaning, especially for the components such as the water tank and steam generator, which are exposed to the water for a particularly long time. The contact breaks can be the same or different. This allows the cleaning fluid to be kept in the steam generator for a particularly long time to counteract the typically high degree of calcification. A cleaning fluid can also be kept in the water tank for a particularly long time to disinfect it particularly thoroughly or to remove microbial films, etc.

[0035] One embodiment allows steps a) to c) to be repeated multiple times. This creates a circuit for the cleaning fluid, allowing particularly effective cleaning even with a small amount of cleaning fluid. In this embodiment, the cleaning fluid pumped back into the receiving container in step c) is pumped back into the water tank in a subsequent step a).

[0036] A further development is that during cleaning mode, the water tank is at least partially filled with water and / or water is added. This provides the advantage that the cleaning fluid can initially be present as a concentrate, which is then diluted by the water. This facilitates the user's handling and storage of the cleaning fluid.

[0037] In a further development, in order to carry out the cleaning mode, a user can, for example, fluidically connect the port to a container (e.g. a bucket, a carafe, a bottle or a specially provided container) in which the cleaning fluid or a corresponding concentrate is located, e.g. via a hose. The third pump pumps the cleaning fluid into the empty or partially filled water tank and, if necessary, more water is added to the water tank. In the process, the connecting line leading from the port to the water tank and the water tank are cleaned. The cleaning fluid is then - optionally according to a predetermined, if necessaryAfter a first exposure pause in the water tank, which depends on the degree of calcification, the cleaning fluid is pumped into the steam generating device by means of the first pump, thereby cleaning the connecting line leading from the water tank to the steam generating device (if present) and the steam generating device. Subsequently, optionally after a predefined second exposure pause in the steam generating device, which may depend on the degree of calcification, the cleaning fluid is pumped back through the port into the container. This also cleans the connecting line leading from the steam generating device to the port. In one variant, the cleaning process is now complete. In another variant, the above steps are carried out again, e.g. for a predefined period of time, which may depend on the degree of calcification.

[0038] In order to increase the effectiveness of the cleaning liquid or cleaning agent, the steam generating device can be switched on during the cleaning mode, in particular in such a way that the temperature of the cleaning liquid increases but advantageously does not boil.

[0039] A further development is that in cleaning mode the cleaning process is followed by a rinsing process. This advantageously removes any residues of the cleaning fluid from the device. In a further development, this can be implemented in such a way that after the cleaning process the used cleaning fluid is emptied from the container by the user, the container is rinsed out and then filled with clean water. To carry out the rinsing process, steps analogous to those for the cleaning process can then be carried out, if necessary without any pause(s). In a particularly user-friendly development, the water is provided by the device, e.g. by letting in fresh water from the mains water supply, so that a user only has to connect the port to an empty container.

[0040] The above-described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an embodiment, which is explained in more detail in connection with the drawings. Fig.1 shows an equivalent circuit diagram of a liquid system of a steam treatment device with three pumps; Fig.2 shows an oblique view of a Fig.1corresponding steam treatment device according to a first embodiment without housing and without door; Fig. 3 shows an oblique view of an enlarged section of the steam treatment device according to the first embodiment in the area of ​​the three pumps; Fig. 4 shows a front view of a sketch of a fluidic connection of the three pumps; and Fig. 5 shows an oblique view of an enlarged section of a steam treatment device with three pumps according to a second embodiment in the area of ​​the three pumps.

[0041] Fig.1 shows an equivalent circuit diagram of a liquid system of a steam treatment device 1. The steam treatment device 1 can be, for example, an oven with steam treatment function, a microwave oven with steam treatment function or an oven with microwave and steam treatment function. It has a by means of a door 24 (see Fig.5) closable steam treatment chamber in the form of a cooking chamber 2 and a steam generating device. The steam generating device is designed here as an evaporator 3 arranged outside the cooking chamber 2. By means of the evaporator 3, the liquid contained therein can be heated, in particular brought to a boil. During steam cooking, the resulting steam is directed from the evaporator 3 into the cooking chamber 2 in order to steam cook the food located therein.

[0042] The steam treatment device 1 further includes a permanently installed water tank 4, which supplies the evaporator 3 with liquid. The water tank 4 can be filled with fresh water via a fixed water connection 5, e.g., by opening and closing a shut-off valve 6.

[0043] The water tank 4 is fluidically connected to a suction side or inlet of a first self-locking pump 8 via a first connector 7. The pressure side or outlet of the first pump 8 is fluidically connected to the evaporator 3 via a second connector 9. The second connector 9 is further connected to an inlet of a second self-locking pump 10. The outlet of the first pump 8 and the inlet of the second pump 10 are thus directly fluidically connected to each other via the second connector 9.

[0044] The outlet of the second pump 10 is connected to a port 12 via a third connector 11, e.g., a connecting piece. A fluid line 13, such as a hose or similar, can be connected to the port 12 in order to fluidically connect the port to a container 14 provided by the user, such as a bucket, carafe, or similar. For this purpose, the fluid line 13 can, for example, simply be hung in the container 14. The third connector 11 is further connected to a suction-side inlet of a third self-locking pump 15, which is fluidically connected at its outlet to the first connector 7 and, via this, to the water tank 4. Consequently, the outlet of the second pump 10 and the inlet of the third pump 15 are directly fluidically connected to one another via the second connector 9, and the outlet of the third pump 15 and the inlet of the first pump 8 are directly fluidically connected to one another via the third connector 7.

[0045] During steam cooking, the second pump 10 and the third pump 15 are deactivated and thus fluidically blocked. When the first pump 8 is operating, practically only water is pumped from the water tank 4 into the evaporator 3 to supply it with water.

[0046] A cleaning operation can be carried out, for example, as follows: First, a user connects the port 12 to the liquid line 13 and inserts the liquid line 13 into the container 14 which is at least partially filled with cleaning liquid. The pumps 8, 10 and 15 are deactivated.

[0047] The third pump 15 is then activated to suck the cleaning fluid from the container 14 and direct it through the third connector 7 into the water tank 4, which may already be partially filled with water. The third pump 15 is then deactivated. Alternatively or additionally, water from the mains water connection 5 can be fed into the water tank 4. If the cleaning fluid is already sufficiently diluted in the container 14, no additional water needs to be added.

[0048] The cleaning fluid can now optionally be left in the water tank 4 for a certain period of time ("action pause").

[0049] In the next step, the first pump 8 is activated to pump the cleaning fluid from the water tank 4 through the first connector 9 into the evaporator 3. The first pump 8 is then deactivated.

[0050] The cleaning fluid can now optionally be left in the evaporator 3 for a specific additional period of time ("action pause"). The evaporator 3 can optionally heat the cleaning fluid for an enhanced cleaning effect, but only to a temperature below boiling point (e.g., 40°C or 50°C) to prevent vapor from the cleaning fluid from entering the cooking chamber 2.

[0051] In a next step, the second pump 10 is activated to pump the cleaning fluid from the evaporator 3 through the second connector 11 and through the port 12 back into the container 14. The second pump 10 is then deactivated.

[0052] This process can now be repeated several times - especially without adding (further) water.

[0053] Once the cleaning process is complete, a similar rinse cycle can be performed. The water used for this can come from the newly filled container 14 with clean water or from the mains water connection 5.

[0054] Alternatively, two or all three pumps 8, 10, 15 can be operated simultaneously, e.g. to enable uninterrupted circulation of the cleaning liquid and / or the clear water.

[0055] Fig.2shows an oblique view of the steam treatment device 1 according to a first exemplary embodiment without a housing and without a door. The evaporator 3, the water tank 4, the pumps 8, 10, 15 and the connecting pieces 7, 9, 11 are arranged above the cooking chamber 2. The fixed water connection 5 can be connected to an Aquastop valve 6, which can conduct fresh water into the water tank 4 via a connecting line 16 that is at least partially hose-like. The first connecting piece 9 is fluidically connected to the evaporator 3 via a further connecting line 17. The second connecting piece 11 is fluidically connected to the port 12 via yet another connecting line 18. The port 12 is accessible to a user on an inside of the cooking chamber 2.

[0056] Fig.3 shows an oblique view of an enlarged section of the steam treatment device 1 in the area of ​​the three pumps 8, 10, 15 and the connecting pieces 7, 9, 11.

[0057] The pumps 8, 10, and 15 and the connecting pieces 7, 9, and 11 are arranged and secured in a water collecting tray 19, arranged parallel to one another and aligned. The pumps 8, 10, and 15 are, in particular, of the same type and have an inlet connection 20 as the inlet and an outlet connection 21 above it as the outlet, as exemplified by the third pump 15.

[0058] The connecting pieces 7, 9, and 11 are designed as straight, tubular connecting pieces, from which two connecting nozzles 22 each extend in the same direction to the pumps 8, 10, and 15. At the front, the connecting pieces 7, 9, and 11 are connected to the water tank 4, the evaporator, and the port 12, respectively.

[0059] The two connecting pieces 9 and 11 are arranged parallel to each other, while connecting piece 7 is inclined relative to each other, so that the connecting pieces 7, 9, and 11 are arranged in an X-shape. In particular, two or three of the connecting pieces 7, 9, and 11 can be mechanically connected to each other, which facilitates their handling—e.g., during assembly—and results in a particularly reliable arrangement.

[0060] Fig.4 shows a front view of the connection-leading end faces of pumps 8, 10 and 15 and a sketch of their fluidic connection with the connection pieces 7, 9 and 11.

[0061] Returning again to Fig.3The water collecting tray 19 serves to collect and drain away free liquid such as condensate, leakage liquid, etc. generated at the pumps 8, 10 and 15 and the connecting pieces 7, 9 and 11. In one variant, the water collecting tray 19 opens at an opening 23 in the water tank 4 so that the free liquid can drain into the water tank 4. In another variant, the water collecting tray 19 is provided (i.e., shaped and arranged) to direct the liquid collected thereby into a drain (not shown). In the latter case, the opening 23 can also be present in order to direct liquid overflowing from the water tank 4 into the water collecting tray 19 into the drain. This prevents the water tank 4 from overflowing beyond its upper edges.

[0062] The water bowl 19 and the water tank 4 are designed here as a one-piece component, for example a plastic injection-molded part.

[0063] Fig.4 shows an oblique view of an enlarged section of a variant of the steam treatment device 1 in the area of ​​the three pumps 8, 10, 15. In this variant, the pumps 8, 10, 15 and the connecting pieces 7, 9, and 11 are not arranged in the water bowl 19, but directly on the top of the cooking chamber 2. In addition, a door 24 closing the front of the cooking chamber 2 is now shown.

[0064] Of course, the present invention is not limited to the embodiment shown.

[0065] In general, "a", "an", etc. can be understood as a singular or a plural, in particular in the sense of "at least one" or "one or more", etc., as long as this is not explicitly excluded, e.g. by the expression "exactly one", etc.

[0066] A numerical value may also include the exact number stated as well as a usual tolerance range, as long as this is not explicitly excluded. List of reference symbols

[0067] 1 Steam treatment device 2 Cooking chamber 3 Evaporator 4 Water tank 5 Permanent water connection 6 Shut-off valve 7 First connection piece 8 First pump 9 Second connection piece 10 Second pump 11 Third connection piece 12 Port 13 Liquid line 14 Container 15 Third pump 16 Connecting line 17 Connecting line 18 Connecting line 19 Water collecting tray 20 Inlet nozzle 21 Outlet nozzle 22 Connecting nozzle 23 Opening 24 Door

Claims

1. Household steam treatment appliance (1), having - a steam treatment compartment (2), - a steam generation facility (3), - a water tank (4) for providing liquid for the steam generation facility (3), an accommodating container (14) and - a pump for pumping liquid out of the accommodating container (14) and into the water tank (4), characterised in that the steam treatment appliance (1) furthermore has - a first pump (8) for pumping liquid out of the water tank (4) and to the steam generation facility (3), and - a second pump (10) for pumping liquid out of the steam generation facility (3) and to the accommodating container (14), - the pump for pumping liquid out of the accommodating container (14) and into the water tank (4) is a third pump (15), and - an input (20) of the first pump (8) and an output (21) of the third pump (15) are connected to a shared first connecting piece (7), which is fluidically connected to the water tank (4), - an output (21) of the first pump (8) and an input (20) of the second pump (10) are connected to a shared second connecting piece (9), which is fluidically connected to the steam generation facility (3) and - an output (21) of the second pump and an input (20) of the third pump (15) are connected to a shared third connecting piece (11), which is fluidically connected to a port (12) for the accommodating container (14), - the pumps (8, 10, 15) are self-locking pumps, or non-locking pumps with a locking valve in each case.

2. Household steam treatment appliance (1) according to claim 1, characterised in that the connecting pieces (7, 9, 11) are shaped as tubes open on one side, and have two connection nozzles (21, 22) branching off from the side for connecting to the corresponding pumps (8, 10, 15), wherein the connection to the water tank (4), the steam generation facility (3) or the accommodating container (14) takes place via a corresponding end open on the end face.

3. Household steam treatment appliance (1) according to one of the preceding claims, characterised in that the pumps (8, 10, 15) are arranged in parallel adjacent to one another and the connecting pieces (7, 9, 11) are straight-line connecting pieces, which are arranged in an X-shape in relation to one another.

4. Household steam treatment appliance (1) according to one of the preceding claims, characterised in that the connecting pieces (7, 9, 11) are connected to one another mechanically.

5. Household steam treatment appliance (1) according to one of the preceding claims, characterised in that the pumps (8, 10, 15) and / or the connecting pieces (7, 9, 11) are arranged in a shared water collection dish (19).

6. Household steam treatment appliance (1) according to claim 5, characterised in that the water collection dish (19) has a drain that leads into the water tank (4).

7. Household steam treatment appliance (1) according to one of claims 5 to 6, characterised in that the water collection dish (19) is produced in one piece with the water tank (4).

8. Household steam treatment appliance (1) according to one of the preceding claims, characterised in that the steam treatment appliance (1) can be operated in at least two operating modes, of which - in a steam treatment operating mode the second pump (10) and the third pump (15) are deactivated; and - in a cleaning operating mode all the pumps (8, 10, 15) can be activated.

9. Method for operating a household steam treatment appliance (1) according to claim 8, in which, in the cleaning operating mode, a) the third pump (15) is activated in order to pump cleaning liquid out of the accommodating container (14) and into the water tank (4); b) the first pump (8) is activated in order to pump the cleaning liquid out of the water tank (4) and into the steam generation facility (3) and c) the second pump (10) is activated in order to pump the cleaning liquid out of the steam generation facility (3) and into the accommodating container (14).

10. Method according to claim 9, in which steps a) to c) are run through in succession.

11. Method according to claim 10, in which exposure pauses are inserted between steps a) to c).

12. Method according to one of claims 10 to 11, in which steps a) to c) are run through multiple times.